276 research outputs found
Charged lepton Flavor Violation in Supersymmetry with Bilinear R-Parity Violation
The simplest unified extension of the Minimal Supersymmetric Standard Model
with bi-linear R-parity violation naturally predicts a hierarchical neutrino
mass spectrum, suitable to explain atmospheric and solar neutrino fluxes. We
study whether the individual violation of the lepton numbers L_{e,mu,tau} in
the charged sector can lead to measurable rates for BR(mu->e gamma)and
$BR(tau-> mu gamma). We find that some of the R-parity violating terms that are
compatible with the observed atmospheric neutrino oscillations could lead to
rates for mu->e gamma measurable in projected experiments. However, the Delta
m^2_{12} obtained for those parameters is too high to be compatible with the
solar neutrino data, excluding therefore the possibility of having measurable
rates for mu->e gamma in the model.Comment: 29 pages, 8 figures. Constraint from solar neutrino data included,
conclusions changed respect v
Bauhinia variegata candida Fraction Induces Tumor Cell Death by Activation of Caspase-3, RIP, and TNF-R1 and Inhibits Cell Migration and Invasion In Vitro
Metastasis remains the most common cause of death in cancer patients. Inhibition of metalloproteinases (MMPs) is an interesting approach to cancer therapy because of their role in the degradation of extracellular matrix (ECM), cell-cell, and cell-ECM interactions, modulating key events in cell migration and invasion. Herein, we show the cytotoxic and antimetastatic effects of the third fraction (FR3) from Bauhinia variegata candida (Bvc) stem on human cervical tumor cells (HeLa) and human peripheral blood mononuclear cells (PBMCs). FR3 inhibited MMP-2 and MMP-9 activity, indicated by zymogram. This fraction was cytotoxic to HeLa cells and noncytotoxic to PBMCs and decreased HeLa cell migration and invasion. FR3 is believed to stimulate extrinsic apoptosis together with necroptosis, assessed by western blotting. FR3 inhibited MMP-2 activity in the HeLa supernatant, differently from the control. The atomic mass spectrometry (ESI-MS) characterization suggested the presence of glucopyranosides, D-pinitol, fatty acids, and phenolic acid. These findings provide insight suggesting that FR3 contains components with potential tumor-selective cytotoxic action in addition to the action on the migration of tumor cells, which may be due to inhibition of MMPs.Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG), Fundação CAPES, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), and FINEP (MCTI/FINEP/MS/SCTIE/DECIT-01/2013-FPXII-BIOPLAT)info:eu-repo/semantics/publishedVersio
Antiproliferative activity of extracts of Euphorbia tirucalli L (Euphorbiaceae) from three regions of Brazil
Purpose: To investigate Euphorbia tirucalli extract for probable geographic variations in its antiproliferative activity.Methods: The aerial parts of E. tirucalli were collected in the Brazilian states of Mato Grosso, Rio de Janeiro, Pará, Minas Gerais and Santa Catarina. The 70 % ethanol extract was obtained according to the procedure described in Brazilian Homeopathic Pharmacopeia. The antiproliferative activity of extracts, in concentrations of 62, 125, 250, and 500 μg mL-1, was tested against leukemia (HL-60), lymphoma (Daudi) and melanoma (B16F10) cell lines using methyl thiazol tetrazolium assay (MTT). Phytochemical analysis were carried out using High-performance liquid chromatography-diode array (HPLC-UV-DAD) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-) FT-ICR MS) assays.Results: There was significant regional variability in the cytotoxicity of E. tirucalli extracts in a dosedependent manner. The extracts had similar activity towards leukemia cell line HL-60, decreasing cell viability to about 60 – 70 %. The extract showed the presence of ellagitannins, flavonoids, veracylglucan, and acid triterpenes as the major compounds.Conclusion: While the results support the ethnopharmacological use of E. tirucalli throughout Brazil, regional quantitative differences found in some classes of secondary metabolites may explain the variations observed in antitumor activity.Keywords: Aveloz, Cancer, Cytotoxicity, Antiproliferative, Ethnopharmacological, Traditional medicin
Spontaneous R-Parity violation bounds
We investigate bounds from tree-level and one-loop processes in generic
supersymmetric models with spontaneous R-parity breaking in the superpotential.
We analyse the bounds from a general point of view. The bounds are applicable
both for all models with spontaneous R-parity violation and for explicit
bilinear R-parity violation based on general lepton-chargino and
neutrino-neutralino mixings. We find constraints from semileptonic B, D and K
decays, leptonic decays of the mu and tau, electric dipole moments, as well as
bounds for the anomalous magnetic moment of the muon.Comment: 22 page
Neutrino Masses and Mixings from Supersymmetry with Bilinear R--Parity Violation: A Theory for Solar and Atmospheric Neutrino Oscillations
The simplest unified extension of the MSSM with bi-linear R--Parity violation
naturally predicts a hierarchical neutrino mass spectrum, in which one neutrino
acquires mass by mixing with neutralinos, while the other two get mass
radiatively. We have performed a full one-loop calculation of the
neutralino-neutrino mass matrix in the bi-linear \rp MSSM, taking special care
to achieve a manifestly gauge invariant calculation. Moreover we have performed
the renormalization of the heaviest neutrino, needed in order to get meaningful
results. The atmospheric mass scale and maximal mixing angle arise from
tree-level physics, while solar neutrino scale and oscillations follow from
calculable one-loop corrections. If universal supergravity assumptions are made
on the soft-supersymmetry breaking terms then the atmospheric scale is
calculable as a function of a single \rp violating parameter by the
renormalization group evolution due to the non-zero bottom quark Yukawa
coupling. The solar neutrino problem must be accounted for by the small mixing
angle (SMA) MSW solution. If these assumptions are relaxed then one can
implement large mixing angle solutions, either MSW or just-so. The theory
predicts the lightest supersymmetic particle (LSP) decay to be observable at
high-energy colliders, despite the smallness of neutrino masses indicated by
experiment. This provides an independent way to test this solution of the
atmospheric and solar neutrino anomalies.Comment: 46 pages, references added + several misprints correcte
Neutrino Physics from Charged Higgs and Slepton Associated Production in AMSB
In the Minimal Supersymmetric Standard Model with bilinear R-Parity
violation, terms that violate R-Parity and lepton number are introduced in the
superpotential, and sneutrino vacuum expectation values are induced. As a
result, neutrino masses and mixing angles are generated via a low energy
see-saw mechanism. We show that this model embedded into an anomaly mediated
supersymmetry breaking scenario is testable at a linear collider using charged
Higgs boson production in association with a stau. This is possible in regions
of parameter space where the charged Higgs and stau have similar mass,
producing an enhancement of the charged scalar mixing angles. We show that the
bilinear parameter and the sneutrino vev can be determined from charged scalar
observables, and estimate the precision of this determination.Comment: 21 pages, including 8 figure
A document management system for the conservation of cultural heritage buildings
A document management system (DcMS) for the efficient organization and visualization of the data related to conservation projects in cultural heritage buildings applied to a case study is presented. The objective of the system is to allow for the interchange of information between different specialists, to prevent the loss of data through time and to promote technical awareness of general public. For this purpose, a database for the management of the information involved in the works carried out in the Monastery of Santa Maria de Salzedas (Portugal) was created. The newly developed system collects the information about the Monastery produced in a period of five years by different specialists (architects, engineers, geologists, physicists and material scientists). The system is fully web based and includes a Back-End for easy uploading of information and a Front-End for automatic visualization and downloading of the information. Both Back- and Front-End are accessible via an Internet connection.The DcMS presented here is part of the project POCTI-HEC-60431-2004, Integrated approach for conservation and valuation of monuments, funded by FCT (Portuguese Science and Technology Foundation). F. Pena acknowledges funding from the FCT grant contract SFRH/BPD/17449/2004. The system was programmed by Engineers Ana Lima and Daniel Oliveira of the Centre of Computer Graphics (CCG)
One-pot intercalation strategy for the encapsulation of a CO-releasing organometallic molecule in a layered double hydroxide
The photoactivatable CO‐releasing molecule (photoCORM) [Mo(CO)3(CNCH2COOH)3] (ALF795) has been incorporated into a Zn,Al layered double hydroxide (LDH) host by a coprecipitation synthesis strategy. Powder X‐ray diffraction (PXRD) of the resultant material Zn,Al‐ALF795 showed that the ALF795 guest molecules assembled into a monolayer to give a basal spacing of 16.0 Å. FTIR and 13C{1H} CP MAS NMR spectroscopy confirmed that the molecular structure of the tricarbonyl complex was retained upon intercalation. Scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS) and elemental analyses confirmed the phase‐purity of Zn,Al‐ALF795. The myoglobin assay was used to demonstrate that intercalated ALF795 retains the photoactive behavior of the free CORM, with a substantial fraction (42 %) of the high CO payload (2.46 mmol g–1) being released after exposure to UV light for 3 h under simulated physiological conditions. In addition, gas chromatography was used to track sequential light‐ and H2O2‐triggered decarbonylation of free and intercalated ALF795. In biological buffer solution (HEPES), less than 2 % Mo leaching from Zn,Al‐ALF795 took place after 5 h, showing the strong capacity of the LDH host to retain the unaltered complex and decarbonylation fragments.publishe
A Supersymmetric Solution to the Solar and Atmospheric Neutrino Problems
The simplest unified extension of the Minimal Supersymmetric Standard Model
with bi-linear R--Parity violation provides a predictive scheme for neutrino
masses which can account for the observed atmospheric and solar neutrino
anomalies in terms of bi-maximal neutrino mixing. The maximality of the
atmospheric mixing angle arises dynamically, by minimizing the scalar
potential, while the solar neutrino problem can be accounted for either by
large or by small mixing oscillations. One neutrino picks up mass by mixing
with neutralinos, while the degeneracy and masslessness of the other two is
lifted only by loop corrections. Despite the smallness of neutrino masses
R-parity violation is observable at present and future high-energy colliders,
providing an unambiguous cross-check of the model.Comment: 5 pages, final version published in Phys. Rev. D61, 2000, 071703(R
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